In general, a flow control device uses a stepping motor or a plurality of solenoid valves to control a flow rate. For example, power is supplied, so the solenoid valves or the stepping motor is operated by using the supplied power to control a flow rate.
The related art bidet controls a flow rate by using a solenoid valve as shown in FIG. 1. In the solenoid valve 1, a plunger 22 is usually in contact with a support body 21 of a diaphragm 20 by virtue of an elastic force of a spring 5 to block an outlet path 15, and when electricity is applied to a solenoid SL, the plunger 22 is lifted up by a magnetic force generated from the solenoid SL, allowing water introduced from an inflow path 10 to flow out to the outflow path 15 through a space part 30.
In the solenoid valve 1, the plunger 30 blocks the outlet path 15 when no electricity is supplied to the solenoid SL, so electrically is constantly supplied in an open state.
In general, in an area in which electricity is applied, a flow rate can be controlled by using the solenoid valve 1. Meanwhile, in an area in which electricity is not supplied, or in order to reduce the use of electricity, power is generated by using water introduced into a self-generation bidet and the bidet is controlled by using generated power. In this case, however, the amount of electricity generated by the introduced water is too small to operate the solenoid valve 1.
A latch valve 2 adaptive to use less power is illustrated in FIG. 2. In the latch valve 2, a magnetic force induced by supplying electricity to a coil of a solenoid SL lifts the plunger 22 up, against the elastic force of the spring 5, and in this case, the plunger 22 can be maintained in an open position by virtue of the magnetic force of a permanent magnet (M), although electricity is not supplied to the solenoid SL. Thus, simply supplying power to open or close the latch valve will do, compared with the solenoid valve 1.
However, in the case of the latch valve which needs power only when it is opened or closed, when the valve is closed, the diaphragm 20 wobbles so as to hit the plunger 22.
In the case of the solenoid valve 1, although the diaphragm 20 wobbles to hit the plunger 22, when the solenoid valve becomes balanced, the solenoid valve is closed, owing to the elastic force of the spring 5 and the self-weight of the plunger 22, but in the case of the latch valve 2, when the plunger 22 is excessively pushed up, the plunger 22 is attached to the permanent magnet, maintaining an open state.
In particular, it may be difficult for the self-generation bidet to continuously or repeatedly use electricity, so the valve is required to be more reliably operated.